A common global understanding on definitions for near-zero emissions and low-emissions materials is a crucial enabler of the industry transition to net zero. These definitions can underpin multiple enabling policy mechanisms to stimulate demand and accelerate deployment of the technologies needed for steel and cement decarbonisation. Clarity on definitions is needed to provide a higher degree of certainty, which would enable the private sector to move forward with the required investments for the transition.

Globally interoperable definitions can be used by countries in policies in accordance with their own circumstances. A common international understanding on definitions is important given the global nature of industrial markets, in order to reduce reporting burden on the private sector and send a clear market signal on the direction of travel. Definitions are a common language or tool, that can then be employed in policies by different countries in line with their own starting points and targeted paces of transition.

Definitions for near-zero emissions and low-emissions materials have distinct and complementary functions. “Near-zero emissions” is specifically reserved for technologies that are already compatible with an energy system at net zero emissions. Distinctive recognition of such performance already today is critical, particularly given the higher risks and costs that come with development and early deployment of innovative technologies. Incentivising these technologies now can help kick-start market uptake, paving the way to eventual widespread diffusion. Meanwhile, the “low-emissions” designation recognises substantial progress and emissions reductions towards the ultimate near-zero goal while not fully achieving it. Given that it will take time for the full market to transition to near-zero emissions technologies, policies that in parallel incentivise scale-up of increasingly lower-emission technologies are also valuable.

To send the required market signal, near-zero emissions definitions should be ambitious and stable, among other characteristics. Common principles can provide a guide and set of guardrails for developing and assessing definitions. Based on emerging proposals and stakeholder discussions, the following principles are proposed for near-zero emissions definitions of materials: ambitious (compatible with the net zero endpoint), stable (the same over time to send a consistent market signal), technology neutral (not excluding any technologies compatible with the net zero endpoint), globally consistent (applies regardless of where materials are produced or consumed to facilitate communication across global markets), physical (technologies are deployed that enable near-zero emissions without offsets or emissions reductions credits), transparent (emissions boundaries, accounting methods and inputs materials are made clear), and accessible (as simple as possible without compromising rigour).

A strong global common understanding is emerging around near-zero emissions threshold values for steel and cement among major proposals to date. In 2022, the IEA Secretariat derived near-zero emissions definitions based on its net zero scenario analyses. For steel, the threshold ranges from 400‑50 kg CO₂ equivalent (CO₂-eq) per tonne of crude steel, depending on the scrap share. For cement, the threshold ranges from 125‑40 kg CO₂-eq per tonne of cement, depending on the clinker ratio. Proposals and use by industry and multi-stakeholder processes are converging around very similar values compatible with the net zero endpoint, including from ResponsibleSteel, the Low Emission Steel Standard, the Global Steel Climate Council, the China Iron and Steel Association, the Industrial Deep Decarbonisation Initiative’s pledge, and the First Movers Coalition, among others. The Global Cement and Concrete Association has translated the cement threshold to the concrete level, arriving at values for near-zero emissions concrete of 21‑36 kg CO₂-eq per metre cubed, depending on the concrete strength. If the international community can continue converging towards existing proposals and using them in a transparent and interoperable manner rather than creating additional new proposals, it would greatly help bring clarity to global markets.

A wider range of approaches to low-emissions definitions has emerged, raising the importance of clear communication and transparency around their use. Since the transition pathway will differ according to regional circumstances, and implies different technology mixes and degrees of emissions reductions over time, the approach to defining low-emissions has greater variation and flexibility than defining near-zero emissions. Still, common principles can guide the development of such definitions, to ensure they support the transition and result in substantial emissions reductions leading towards the ultimate near-zero goal. The following principles are proposed for low-emissions definitions of materials: ambitious, with clear communication on the ambition level; signals need for progressive improvement over time; technology neutral; global coherence while accounting for regional starting points; clear communication on chain of custody; transparent; and accessible. The principles are in parallel to those for near-zero emissions but take into account the broader potential and the wider diversity of approaches for low-emissions definitions.

Emissions measurement methodologies underpin definitions, as well as multiple other mechanisms to enable the industrial transition. Existing emissions measurement methodologies (such as International Organization for Standardization [ISO] standards, EU Environmental Footprint Methods) and emissions reporting and labelling tools (such as Environmental Product Declarations, Digital Product Passports) already provide a robust basis for measuring steel and cement emissions, and should be used wherever possible in policies and for evaluation with respect to meeting definitions thresholds.

Updates and revisions may be needed to ensure these existing methodologies and reporting tools are fit-for-purpose. The IEA Secretariat has proposed to follow its Net Zero Measurement Principles to guide revisions of emissions measurement methodologies towards increasing interoperability and net zero compatibility; facilitate like-for-like comparison between production from all facilities; produce coherent and interoperable results for both production and products; have a comprehensive emissions boundary and scope that covers the main sources of emissions in the supply chain; apply net zero compatible accounting rules for emissions credits and co-products; and incentivise the use of site- and product-specific auditable measured data. Increasing stakeholder engagement in the processes of standards bodies, including ISO and regional and national standards bodies, could help accelerate such revisions.